Serpinema pelliculatus Silva, Jesus and Melo, 2023

Silva, Leandro Mauricio Oliveira, Jesus, Ronald Ferreira, Santos, Ana Nunes, Nandyara, Bianca, Willkens, Yuri, Santos, Jeannie Nascimento & Melo, Francisco Tiago Vasconcelos, 2023, New species of Serpinema (Nematoda: Camallanidae) from the scorpion mud turtle Kinosternon scorpioides (Testudines: Kinosternidae) from eastern Amazon, Brazil, International Journal for Parasitology: Parasites and Wildlife 22, pp. 6-13 : 7-9

Serpinema pelliculatus Silva, Jesus and Melo n. sp. ( Figs. 1–3 )

Type host: Kinosternon scorpioides Linnaeus, 1766

Type locality: Soure – Ilha de Marajo´(00 ◦ 43′00"S 48 ◦ 31′24"O), Par´a, Brazil .

Additional locality: Abaetetuba (01 ◦ 43′05"S 48 ◦ 52′57"O), Par´a, Brazil .

Site of infection: Stomach and intestine.

Prevalence and mean intensity: 87,5% (21 infected hosts out of 24 analyzed) and 4,71 (range of infection 1–12; 99 nematodes were found in all hosts, most of the specimens were females).

Specimens deposited: Holotype ( MPEG. PLA 000399 ), allotype ( MPEG. PLA 000400 ), 10 male paratypes ( MPEG. PLA 000401 ) and 10 female paratypes ( MPEG. PLA 000402 ) deposited in the Other Invertebrate Collection of Museu Paraense Emílio Goeldi , Par´a, Brazil.

ZooBank registration: To comply with the regulations set out in article 8.5 of the amended 2012 version of the International Code of Zoological Nomenclature ( ICZN, 2012), details of the new species have been submitted to ZooBank. The Life Science Identifier (LSID) for Serpinema pelliculatus n. sp. is urn:lsid:zoobank.org:act:66B8B1FC-0EE2-419C-9999-97F97E6A5E65 .

Etymology: The specific epithet refers to the morphology of the

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spicule that is covered by a sheath. Pelliculatus = covered over with skin or skins or pellicles.

3.2. Description

General: Medium to large-sized nematodes. Translucent red in life, with thin transverse cuticular striations. Body with truncated anterior end ( Fig. 1A and B ). Mouth opening in transverse slit; 2 pairs of cephalic papillae (1 latero-ventral pair and 1 latero-dorsal pair); a pair of lateral amphids ( Fig. 1G ). Buccal capsule composed of 2 concave lateral valves; 2 pairs of curved sclerotized structures on the anterior part the valves ( Fig. 1F, I ; 3A ). Valves internally marked by longitudinal complete ridges (extending from anterior to posterior margin of buccal capsule) and incomplete ridges (shortly distant from anterior margin of buccal capsule) ( Fig. 1C and D ). Tridents, 1 ventral and 1 dorsal, composed of a slightly rounded basal portion and 3 divergent branches; median branch shorter; lateral branches similar in size ( Fig. 1H ). Chitinous basal ring between buccal capsule and esophagus ( Fig. 1E ). Esophagus divided into

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a short muscular anterior portion and a glandular posterior portion ( Fig. 1A and B ). Nerve ring at anterior part of the muscular esophagus. Excretory pore at posterior half of muscular esophagus ( Fig. 1A and B ). Deirids not observed.

Males [based on holotype and 10 paratypes; measurements of holotype followed by range of paratypes in parenthesis]: Total length 6.45 (6.07–8.20) mm. Width at mid-body 227 (173–240). Buccal capsule 84 (60–91) × 100 (95–109). Buccal valves with 8 (8–8) complete ridges, 1 (1–3) incomplete ridges. Trident middle branch 67 (48–69) long; trident lateral branches 73 (60–85) long. Basal ring 12 (8–13) × 74 (60–79). Esophagus total length 976 (819–976). Muscular esophagus 363 (317–363) × 136 (99–139). Glandular esophagus 613 (499–613) × 152 (115–155). Nerve ring 195 (141–203) and excretory pore 352 (304–357) from the anterior end. Caudal alae well-developed, starting at the level of a vesicular-like globular protrusion, ending near tail tip ( Fig. 2A ). Fifteen pairs of pedunculate caudal papillae. Seven pairs pre cloacal: all lateral pairs. Two pairs ad cloacal: ventral and anterior to cloaca. Six pairs post cloacal: first, second and third pairs clustered close to cloaca; fourth and fifth pairs grouped, situated near mid-tail length; sixth pair close to tail end ( Fig. 2A and B ; 3E ). One robust, sharp-edged spicule 477 (416–566) long, covered by a sheath ( Fig. 2C ). Gubernaculum absent. Tail ventrally curved 131 (83–131) long; strong transverse musculature ( Figs. 2A and 3E ).

Females [based on allotype and 10 paratypes; measurements of allotype followed by range of paratypes in parenthesis]: Total length 8.31 (8.05–9.91) mm. Width at mid-body 227 (227–333). Buccal capsule 96 (84–100) × 119 (97–119). Buccal valves with 8 (8–8) complete ridges, 3 (1–3) incomplete ridges. Trident middle branch 77 (48–80) long; trident lateral branches 92 (81–104) long. Basal ring 13 (10–17) × 86 (74–88). Esophagus total length 0.94 (0.94–1.12) mm. Muscular esophagus 368 (368–416) × 115 (115–141). Glandular esophagus 571 (560–699) × 125 (125–203). Nerve ring 197 (171–221) and excretory pore 339 (339–437) from the anterior end. Vulva close to mid-body; slightly post equatorial; prominent lips; more developed posterior lip; situated 3.71 (3.71–4.64) mm from the posterior end ( Fig. 2E ; 3B ), at 55.37% (51.02%–56.06%) of the total length. Tail, 140 (140–197) long ( Fig. 2D ; 3C ), ending with 3 small projections, 1 dorsal and 2 ventrolateral ( Fig. 3D ). Vulva-anus distance 3.55 (3.55–4.44) mm. Viviparous. Uterus with several larvae ( Fig. 2E ).

Figures

Fig. 1. Line drawings of Serpinema pelliculatus n. sp. (a) Anterior region of female, lateral view. (b) Anterior region of male, lateral view. (c) Buccal capsule of female, lateral view. (d) Buccal capsule of male, lateral view. (e) Basal ring, apical view. (f) Anterior curved sclerotized structures, lateral view. (g) Cephalic extremity of male, apical view (h) Trident of male, ventral view. (i) Buccal capsule of male, apical view.

Fig. 2. Line drawings of Serpinema pelliculatus n. sp. (a) Posterior region of male, lateral view. (b) Posterior region of male, ventral view. (c) Spicule, ventral view. (d) Posterior region of female, lateral view. (e) Vulva, lateral view.

Fig. 3. Scanning electron microscopy of Serpinema pelliculatus n. sp. (a) Anterior end of male, subventral view; (b) Vulva, subventral view. (c) Posterior region of female, ventral view. (d) Tip tail of female, ventrolateral view. (e) Posterior region of male, subventral view (arrowheads indicate papillae). Abbreviations: anterior lip, Al; anus, An; posterior lip, Pl; trident, Tr.